I added a dropbox web connection with my concern user, everything worked out. After that, I wanted to add another dropbox web connection, but this time with another user. Unfortunately the login did not work out (see screenshot). I tried to clear cache and cookies from my standard browser, change standard browser to be sure that nothing is cached in the background, but still the same message appeared. I also tried to delete the other web connection, but still same issue occured.
Does anyone have ideas how to solve this?
